In wireless communication systems, portable or mobile subscriber units communicate with a centrally located base station within a cell. The wireless communication systems may be a CDMA2000, GSM and WLAN communication system, for example. The subscriber units are provided with wireless data and/or voice services and can connect devices such as, for example, laptop computers, personal digital assistants (PDAs), cellular telephones or the like through the base station to a network.
Each subscriber unit is equipped with an antenna. To increase the communications range between the base station and the mobile subscriber units, and for also increasing network throughput, smart antennas may be used. Smart antennas may also be used with access points and client stations in WLAN communication systems. A smart antenna includes a switched beam antenna or a phased array antenna, for example, and generates directional antenna beams.
Example smart antennas are disclosed in U.S. Pat. Nos. 6,369,770 and 6,480,157. Both of these patents are assigned to the current assignee of the present invention, and are incorporated herein by reference in their entirety. Antennas in general have limited bandwidth, and smart antennas also exhibit this same behavior.
With the emergence of new wireless applications, there is a demand for smart antennas having a wider bandwidth than had been previously developed. A wider bandwidth often requires a more complex design, which could increase antenna loss. Alternatively, reactive components can be added to increase the bandwidth, but this adds to the cost of a smart antenna.